Tufting machines

ABSTRACT

An adjustable jerker bar mechanism for a tufting machine includes first and second jerker bars secured to the machine frame and the needle bar respectively, the first such jerker bar comprising a composite structure which includes a movably mounted jerker bar supported by spaced swinging arms and an adjustment means for varying the angular position of such arms relative to a datum and thereby adjusting the relative positions of the first and second jerker bars at an extreme position thereof.

United States Patent Parsons [1 1 3,738,293 1 June 12, 1973 1 TUFTlNG MACHINES [75] Inventor: Ronald Parsons, Rishton, Blackburn,

Lancashire, England [73] Assignee: The Singer Company (U.K.)

Limited, London, England 221 Filed: Aug. 13,1971

211 Appl. No.: 171,663

[30] Foreign Application Priority Data Aug. 22, 1970 Great Britain 40,560/70 [52] U.S. Cl 112/79 R [51] Int. Cl. D056 15/18 [58] Field of Search 112/79 R, 79 A, 266,

[56] References Cited FOREIGN PATENTS OR APPLICATIONS 1,178,589 1/1970 Great Britain 112/79 A Primary ExaminerJames R. Boler Attorney-Marshall .l. Breen, Chester A. Williams and Julian Falk [5 7] ABSTRACT An adjustable jerker bar mechanism for a tufting machine includes first and second jerker bars secured to the machine frame and the needle bar respectively, the first such jerker bar comprising a composite structure which includes a movably mounted jerker bar supported by spaced swinging arms and an adjustment means for varying the angular position of such arms relative to a datum and thereby adjusting the relative positions of the first and second jerker bars at an extreme position thereof.

7 Claims, 3 Drawing Figures PATENIED JimI 3; 738 2 93 SHEET 1 0F 2 PAIENIE Jun 2 I973 sum 2 0F 2 TUFTING MACHINES The invention concerns tufting machines and has more particular reference to a jerker bar arrangement therefor.

The provision of a jerker bar movable in synchronism with the needle bar of a tufting machine and operating on the yarns passing to the needles on the upstroke of the needles to tighten the yarn against the reverse face of the backing fabric is now widely followed, such jerker bar co-operating with a fixed jerker bar or bars on the machine to vary the path length between the yarn feed rollers and the needles to effect the pull-back necessary for tightening purposes.

In known constructions the moving jerker bar is carried by the needle bar for movement therewith, and at a fixed position relative thereto, whilst the fixed bar with which such jerker bar co-operates is likewise arranged in fixed disposition upon the framework of the machine. In consequence, the path length for yarn moving to the needle is variedby a set amount determined by the geometry of the situation, and will remain constant under all circumstances of operation of the machine.

However, according to tufting conditions and the yarn in use, optimum tufting performance may require a variation in path length different from that which results from the geometry of the machine and particularly of the jerker mechanism thereof.

' It is known to provide a limited and coarse adjustment for the fixed jerker bar by mounting the same at a selected one of a range of positions on a support bracket, such bracket being provided with an elongate slot for this purpose. However, the accuracy of the adjustment leaves much to be desired and does, furthermore, not permit of the effecting of an adjustment with the machine in operation.

' The primary object of the present invention is to provide an improved means whereby an accurate adjustment in the path length variation introduced by the jerker mechanism is possible in a ready and simple manner.

According to the present invention an adjustable jerker bar mechanism for a tufting machine comprising a first jerker bar mounted on the tufting machine framework to extend transversely of the machine and in spaced parallel disposition relative to the needle bar and a second jerker bar mounted relative to the needle bar for movement therewith, the second jerker bar likewise being arranged parallel to the needle bar, is characterised in that at least one of the said jerker bars comprises a composite structure including a movably mounted jerker bar and an adjustment means adapted to displace such movable bar in the transverse direction thereof so as effectively to vary the separation of the first and second bars in an extreme relative disposition of such bars and to maintain a selected separation of such bars.

. According to a preferred construction the adjustable jerker bar is mounted on a swinging arm or arms and the adjustment means is adapted to vary the angular disposition of such arms relative to a datum position to adjust the position of the jerker bar in a direction transverse thereto.

According to a further feature of the'invention the adjustment means includes an elongate, longitudinally shiftable intermediate member adjustably mounted relative to the needle bar and a cam and cam follower means are provided for converting a displacement of an intermediate member in a first direction into a displacement of the jerker bar in a second direction at right angles thereto.

In one arrangement the displacement of the intermediate member in the said first direction is effected by means comprising a screw-threaded rod axially fixed but rotatable in a thrust block secured to the machine frame and an adjustment nut engaged with the said rod and constrained against rotation therewith, the said adjustment nut being secured to the intermediate memher.

The invention will now be described further, by way of example only, with reference to the accompanying drawings illustrating one embodiment thereof and in which:

FIG. 1 is a diagrammatic perspective view of an adjustable jerker bar mechanism as applied to a tufting machine:

FIG. 2 is an end elevation, partly in section, of a jerker bar machanism of the kind shown in FIG. 1; and

FIG. 3 is a section taken through a part of the mechanism shown in FIG. 2 and taken on a line corresponding to line III-11] of FIG. 1.

Referring now to the drawings, in which like reference numerals are used for corresponding parts in the different views, an adjustable jerker bar mechanism for a tufting machine includes a first jerker bar 11 supported on the needle bar 12 for movement therewith, the said first bar 11 being arranged in spaced parallel disposition relative to the needle bar and being mounted thereon by brackets 13 (FIG. 2) extending transversely therefrom and at intervals therealong. The jerker bar is of conventional form and comprises a flat,

elongate bar provided with a multitude of through holes lla therein each to receive a respective yarn 14 as is clearly shown in FIG. 1.

The mechanism further includes a second jerker bar 16 arranged in spaced parallel disposition relative to the first such jerker bar, the second jerker bar being mounted on the top beam 17 of the machine and being adjustable up or down relative to such top beam by means hereafter to be described. The second jerker bar 16 likewise comprises an elongate bar-having through holes 16a therein, and such bar is supported at the lower end of a plurality of support brackets 18 arranged at intervals along the bar, the upper ends of the said brackets being secured to a jerker carrier 19. In order to permit of an adjustment of the jerker bar 16 relative to the jerker carrier 19, the brackets 18 are provided with elongate slots 18a through which clamping bolts 21 pass, a respective clamping plate 22 being interposed between the head 21a of each bolt and the bracket 18 it serves to secure.

The jerker carrier 19 consists of a rigid bar supported by spaced, parallel swinging arms 23 (only one of which is shown), the said arms being pivotally mounted at one end thereof on the said top beam by a pin 24 and the other end of each arm being connected with the jerker carrier 19 by a bolt 26 which extends through a respective slot 27 provided in an intermediate member formed as a cam-slot plate 28 mounted on the front of the top beam in suitable guides 29 and for movement lengthwise of such beam, the cam-slot plate 28 being positioned between the jerker carrier 19 and the swinging arms 23. The bolts 26 securing the carrier 19 and swinging arms 23 together are provided with sleeves 26a (FIG. 3) thereabout, the bolts, together with their co-axial sleeves, being a close but free fit within the cam slots 27 for motion therealong.

An adjustment means 31 is provided for shifting the cam-slot plate 28 in the longitudinal direction thereof, such means including a screw-threaded rod 32 captively engaged with a thrust block 33 attached to the machine frame and positioned within a slot 28a provided at the end of such plate, the said rod 32 being rotatable in the said block 33 but being axially fixed relative thereto. The means further includes an adjustment nut 34 likewise located in the slot 28a and screwthreadedly engaged by the rod 32, rotation of the rod 32 within the thrust block 33 causing the nut 34 to move longitudinally of the rod and thus the cam-slot plate, to which plate the adjustment nut 34 is secured, to left or right in the guides 29.

Upon a longitudinal shift of the cam-slot plate 28 consequent upon rotation of the rod 32, which rotation is facilitated by the provision of a ratchet key 36 thereon, the swinging arms 23 are pivoted up or down about their respective pivot axes by the movement of the bolts 26 in the inclined cam slots 27 and the jerker carrier 19 is moved accordingly.

In use, a coarse adjustment of the position of the second jerker bar 16 is effected by appropriately positioning the brackets 18 relative to the jerker carrier 19 and a fine adjustment of such position is effected by means of the adjustment means 31 provided at the end of the cam slot plate 28.

It will readily be appreciated that, whereas adjustment by means of the brackets 18 can only be effected when the machine is stopped, since an appropriate adjustment will be required at each bracket and the need to maintain a tension in the yamsmoving to the machine and to provide for backstitch tightening at each stitch would militate against a simultaneous slackening off of all of the bolts 21 whereby the brackets are attached to the jerker carrier 19, the same difficulty does not exist in the case of the adjustment means 31 whereby the jerker carrier is raised or lowered by pivotal motion of the swinging arms 23 since the yarns remain under tension at all times and the adjustment in position occurs simultaneously at all positions lengthwise of the jerker bar.

We believe that by means of the adjustment means herein described we provide a simple yet affective adjustment means which will allow of a ready adjustment in the variation in path length at the jerker bar mechanism to a high degree of accuracy within the range of possible adjustment as determined by the angle of the slot and the extent of possible shift of the plate. Furthermore, by providing the adjustment means in a readily accessible position so, too, are we able to effect adjustment even during operation of the machine and thereby provide a facility for a most accurate adjust-' as to position relative to the jerker carrier, in no way is the invention limited to this feature.

Alternative means may be provided, if preferred, for

effecting the longitudinal shift of the cam-slot plate,

and to this end a wedge-cam operating on the said plate could be used.

What we claim is:

1. An adjustable jerker bar mechanism for a tufting machine which includes a frame in which a needle bar is carried for reciprocating movement therein, comprising a first jerker bar carried pivotably by said frame to extend transversely of the machine and in spaced parallel disposition relative to the needle bar and a second jerker bar carried by said needle bar parallel thereto for movement therewith, an adjustment means being provided adapted to displace said first jerker bar at least in the transverse direction thereof so as effectively to vary the separation of the first and second bars and to maintain a selected separation of such bars.

2. An adjustable jerker bar mechanism for a tufting machine which includes a frame in which a needle bar is carried for reciprocating movement therein, comprising a first jerker bar carried by said frame to extend transversely thereof and'in spaced parallel disposition relative to the needle bar and a second jerker bar carried by said needle bar parallel thereto and for movement therewith, at least one of said jerker bars comprising a composite structure including a movable jerker bar supported on at least one swinging arm carried by said frame, an adjustment means being provided adapted to displace said movable bar in the transverse direction thereof, said adjustment means being adapted to vary the angular position of such arm relative to a datum position to adjust the position of the jerker bar in a direction transverse thereto so as effectively to vary the separation of the first and second bars and to maintain a selected separation of such bars.

3. An adjustable jerker bar mechanism as claimed in claim 2 wherein the adjustment means includes an elongate longitudinally shiftable intermediate member adjustably carried by said frame relative to the needle bar and a cam and cam follower mechanism connecting such intermediate member and the movable jerker bar,

the said mechanism being adapted to convert a displacement of the intermediate member in a first direction into a displacement of the jerker bar in a second direction at right angles to the said first direction 4. An adjustable jerker bar mechanism as claimed in claim 3 wherein the cam and cam follower mechanism comprises a slot in the said intermediate member which is inclined relative to the longitudinal axis of such member and a cam follower operating in the said slot, the cam follower being connected with and supporting the movable jerker bar relative to such slot.

5. An adjustable jerker bar mechanism as claimed in claim 4 wherein the cam follower is connected with a claim 3 wherein the movable. jerker bar is adjustably I mounted on the said intermediate member.

a s a a m 

1. An adjustable jerker bar mechanism for a tufting machine which includes a frame in which a needle bar is carried for reciprocating movement therein, comprising a first jerker bar carried pivotably by said frame to extend transversely of the machine and in spaced parallel disposition relative to the needle bar and a second jerker bar carried by said needle bar parallel thereto for movement therewith, an adjustment means being provided adapted to displace said first jerker bar at least in the transverse direction thereof so as effectively to vary the separation of the first and second bars and to maintain a selected separation of such bars.
 2. An adjustable jerker bar mechanism for a tufting machine which includes a frame in which a needle bar is carried for reciprocatiNg movement therein, comprising a first jerker bar carried by said frame to extend transversely thereof and in spaced parallel disposition relative to the needle bar and a second jerker bar carried by said needle bar parallel thereto and for movement therewith, at least one of said jerker bars comprising a composite structure including a movable jerker bar supported on at least one swinging arm carried by said frame, an adjustment means being provided adapted to displace said movable bar in the transverse direction thereof, said adjustment means being adapted to vary the angular position of such arm relative to a datum position to adjust the position of the jerker bar in a direction transverse thereto so as effectively to vary the separation of the first and second bars and to maintain a selected separation of such bars.
 3. An adjustable jerker bar mechanism as claimed in claim 2 wherein the adjustment means includes an elongate longitudinally shiftable intermediate member adjustably carried by said frame relative to the needle bar and a cam and cam follower mechanism connecting such intermediate member and the movable jerker bar, the said mechanism being adapted to convert a displacement of the intermediate member in a first direction into a displacement of the jerker bar in a second direction at right angles to the said first direction.
 4. An adjustable jerker bar mechanism as claimed in claim 3 wherein the cam and cam follower mechanism comprises a slot in the said intermediate member which is inclined relative to the longitudinal axis of such member and a cam follower operating in the said slot, the cam follower being connected with and supporting the movable jerker bar relative to such slot.
 5. An adjustable jerker bar mechanism as claimed in claim 4 wherein the cam follower is connected with a jerker bar carrier, and the movable jerker bar is adjustably mounted on such carrier.
 6. An adjustable jerker bar mechanism as claimed in claim 3 wherein the adjustment means further includes an arrangement adapted to effect the longitudinal shift of the intermediate member and comprising a screw-threaded rod axially fixed but rotatable in a thrust block secured to the machine frame and an adjustment nut engaged with the said rod and constrained against rotation therewith, the said adjustment nut being secured to the intermediate member.
 7. An adjustable jerker bar mechanism as claimed in claim 3 wherein the movable jerker bar is adjustably mounted on the said intermediate member. 